This invention relates to the fusing of toner images. More specifically, it relates to the control of a pressure roller fuser which has a "run" condition in which it is actually fusing toner images to a receiving sheet and a "standby" condition in which it is ready to fuse toner images. A modem copier or printer may be in standby condition 95% of a working day.
Some pressure roller fusers used commercially are not separated during their standby condition to save the cost of the separating structure and to improve reliability. Since the fuser is kept warm during standby, the rollers are usually continuously rotated in most such structures to prevent heatset of the more compliant of the rollers. Although heatset is prevented, continuously running the fuser during standby substantially reduces the life of pans, for example, the bearings and the rollers themselves.